Convert Microinch to Pole
Convert microinches to poles instantly. 1 microinch = 5.050505e-9 pole — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Pole to Microinch converter for the reverse conversion.
Units explained
Microinch
A microinch is an Imperial unit of length equal to one millionth of an inch (2.54×10⁻⁸ m). It is used almost exclusively in surface-finish specifications for precision machining and optical components.
The microinch is derived from the inch using the SI-style prefix micro- to denote one millionth. Standardised through the 1959 International Yard and Pound Agreement, which fixed the inch at exactly 25.4 mm.
Microinches express surface roughness (Ra values) in US-based precision manufacturing — typical machined surfaces are 16–125 µin. Optical components and bearing races are often specified to 1–4 µin Ra.
Used in US precision-manufacturing literature throughout the 20th century; value became exact in 1959 when the inch was fixed at 25.4 mm via the International Yard and Pound Agreement.
Pole
A pole is an Imperial unit of length identical to the rod and perch — 16.5 feet (about 5.03 m). The names are regional and historical variants for the same measurement.
The pole derives from medieval English land-surveying. The name comes from the physical wooden pole used by surveyors to lay out the unit on the ground.
Poles appear in historical land records, particularly older US public-land surveys. Functionally identical to rod and perch in all calculations.
Medieval English surveying origin; identical to the rod since 1620; became exact via the 1959 International Yard and Pound Agreement.
Microinch to Pole conversion formula
The relationship between microinches and poles:
To convert microinches to poles, multiply the value in microinches by 5.050505e-9. To reverse, multiply poles by 1.98e+8.
How to use this converter
Type a value into the calculator. The result in poles updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Pole to Microinch converter for the reverse direction.
Step-by-step: convert microinches to poles
- Write down the value in microinches (µin).
- Multiply that value by the factor 5.050505e-9.
- The product is the equivalent value in poles (pole).
- To reverse, multiply the pole value by 1.98e+8.
Worked examples
Example 1 — Convert 1 µin to pole:
1 × 5.050505e-9 = 5.050505e-9 pole
Example 2 — Convert 100 µin to pole:
100 × 5.050505e-9 = 5.050505e-7 pole
Real-world example — Bridging nine orders of magnitude
500 million microinches equals a value comfortably in the human-scale poles range. Physics problems that span this gap are common when comparing the wavelength of light to the path length of an experiment.
5e+8 µin × 5.050505e-9 = 2.5252525253 pole
Real-world example — From sub-micron to human scale
One billion microinches equals one pole — the conversion that drives home the gulf between atomic-scale features and everyday objects in physics curricula.
1e+9 µin × 5.050505e-9 = 5.0505050505 pole
Microinch to Pole conversion table
Standard reference values for converting microinches to poles:
| Microinch [µin] | Pole [pole] |
|---|---|
| 0.01 | 5.050505e-11 |
| 0.1 | 5.050505e-10 |
| 1 | 5.050505e-9 |
| 2 | 1.010101e-8 |
| 3 | 1.515152e-8 |
| 4 | 2.020202e-8 |
| 5 | 2.525253e-8 |
| 10 | 5.050505e-8 |
| 20 | 1.010101e-7 |
| 30 | 1.515152e-7 |
| 40 | 2.020202e-7 |
| 50 | 2.525253e-7 |
| 100 | 5.050505e-7 |
| 500 | 2.525253e-6 |
| 1000 | 5.050505e-6 |
Frequently asked questions
How many poles is 1 microinch?
How do I convert microinches to poles?
How do I convert poles back to microinches?
How many poles is 100 microinches?
Popular length unit conversions
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Imperial / US Customary (26 units)
Sources & references
Conversion factor (1 µin = 5.050505e-9 pole) verified against the following authoritative sources:
- BIPM — The International System of Units (SI Brochure 9th ed.)
Official BIPM publication defining the seven SI base units (including the meter) and the rules for their use. The global authority on units of measurement.
- NIST — Guide to the SI
US National Institute of Standards and Technology reference covering the SI base and derived units with definitions and usage rules for US technical practice.
- NIST Special Publication 811 — Guide for the Use of the International System of Units
Detailed NIST guide covering exact conversion factors between SI and US customary units along with formatting and rounding conventions.
- NIST — Refinement of values for the yard and pound (Federal Register 1959)
The treaty (signed by US
- International Hydrographic Organization — Resolution on the Nautical Mile
International authority that standardised the nautical mile at exactly 1852 m in 1929 — the value adopted worldwide for sea and air navigation.